Chief engineering officer

On starships or starbases, the chief engineering officer (often shortened to chief engineer) is in charge of all engineers and engineering duties.

The chief engineer's duties range from making the duty shift roster for engineering personnel to advising the captain on possible solutions for certain technical problems. In general the chief engineer is an officer with enough experience in his or her own field of expertise and with seniority over the rest of the engineers. A chief engineer is also a member of the senior staff and accountable for the overall performance of the vessel.

In the context of engineering, the chief engineer may be seen giving orders to persons who would ordinarily outrank him in other contexts, e.g., the second officer. For example, Data regularly takes orders from Geordi La Forge in engineering contexts, even though as the second officer Data outranks Geordi in absolute terms. (TNG)

The captain of a Starfleet starship has the prerogative to appoint someone to the post of chief engineer even if he or she does not have the seniority which normally would apply to this function. Persons with vast experience and engineering knowledge but no appropriate Starfleet rank could be appointed as chief engineer in this manner. (VOY: "Parallax")

Argyle appeared to have replaced Sarah MacDougal as Chief Engineer and was apparently replaced himself by LieutenantLogan prior to TNG: "The Arsenal of Freedom", who was in turn seemingly replaced by Leland Lynch by TNG: "Skin of Evil". However, CommanderWilliam T. Riker's line in "Where No One Has Gone Before" that engineering matters were overseen by "one of our chief engineers, in this case, [Mr.] Argyle" seems to imply that the ship had more than one chief engineering officer at the time. Therefore, it is possible that MacDougal and Argyle both served as chief engineer simultaneously. This practice of having more than one chief engineer seems to have come to an end by 2365, when Geordi La Forge became the sole chief engineer of the Enterprise. It is also however possible that the term chief engineers actually applied to the most senior engineers (Possibly the three most senior as typically three shifts will be run in a day so there would have to be at least three engineers who would run the department during their own shifts) however chief engineer was still an individual position in its own regard. This multiple application of titles has been seen before with regard to the title of Commanding Officer, which can be used to apply to the single position of the highest ranking officer in command of a starship or starbase or also to the person whom one directly reports to in the chain of command or in a department.